Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied 608 consecutive cases of anti-HCV-positive chronic liver disease. In 358 patients the diagnosis was established by needle liver biopsy. In 250 patients with liver cirrhosis the diagnosis was made on the basis of the unequivocal clinical signs and the results of imaging procedures. Chronic HCV infection is usually observed in adults or elderly patients; the age of the patients steadily increases with the progression of the illness to the more severe stages. Jaundice was infrequent in patients with chronic hepatitis or early cirrhosis; clinical symptoms and laboratory tests are of little value in differentiating CPH from CAH or in detecting early cirrhosis. Serum aminotransferases were usually only slightly elevated in all stages of the disease. Despite the mildness of the hepatic cytolysis, the progressive reduction in serum cholinesterase and albumin concentrations and the progressive increase in the serum alkaline phosphatase activity indicate progressive failure in the hepatic function in the course of the illness. The histological study showed that steatosis, follicular portal inflammation and eosinophilic changes in the hepatocytes were prominent features of chronic HCV infection. In contrast, severe piecemeal necrosis without bridging was rarely observed.
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PMID:Clinical and histological aspects of chronic HCV infection and cirrhosis. 840 7

Chlorpyrifos (CPF), a commonly used cholinesterase-inhibiting insecticide, is lethal at much lower doses to young animals than adults. To explain this higher sensitivity in younger animals, we hypothesized that young rats have less chlorpyrifos-oxonase (CPFOase) activity than adults. To test this hypothesis, CPFOase activity was measured in the brain, plasma, and liver of male, postnatal day 4 (PND4) and adult (PND90) Long-Evans rats. CPFOase is biochemically defined as a Ca(2+)-dependent A-esterase that hydrolyzes chlorpyrifos-oxon (CPFO), the active metabolite of CPE. No brain CPFOase activity was detected at either age. Plasma and liver CPFOase activities were markedly lower at PND4 compared to adult: PND4 plasma and liver CPFOase activities were 1/11 and 1/2 the adult plasma and liver activities, respectively. Because the Km of CPFOase activity was high (i.e., 210-380 microM), it was important to determine if this CPFOase activity could hydrolyze physiologically relevant concentrations (i.e., nM to low microM) of CPFO. This was accomplished by comparing the shifts in the tissue acetylcholinesterase (AChE) IC50 for CPFO in the presence or absence of CPFOase activity. One would expect an increase in the "apparent" IC50 if CPFOase hydrolyzes substantial amounts of CPFO during the 30 minutes the tissue is preincubated with the CPFO. In the adult, both plasma and liver AChE apparent IC50 values were higher in the presence of CPFOase activity, suggesting that the CPFOase in those tissues was capable of hydrolyzing physiologically relevant concentrations of CPFO within 30 minutes. In young animals, however, there was less of a shift in the IC50 curves compared to the adult, confirming that the young animal has less capacity than the adult to detoxify physiologically relevant concentrations of CPFO via CPFOase.
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PMID:Maturational differences in chlorpyrifos-oxonase activity may contribute to age-related sensitivity to chlorpyrifos. 926 78

Three acetylcholinesterase (AChE) forms were detected and recovered from foot or gill tissues of the benthonic bivalve mollusk Scapharca inaequivalvis. A study was performed to investigate changes in catalytic and hydrodynamic features of these enzymes, as well as in their expression levels, after a 4-d or a 15-d exposure to a sublethal concentration (0.1 microl/L) of the pesticide chlorpyrifos (CPF). Both considered organs hold, in either CPF-exposed or untreated animals, two nonamphiphilic AChE forms, G2 and G4, which copurified on a procainamide-containing affinity gel and were separated by density gradient centrifugation. A third AChE form, an amphiphilic membrane-anchored G2, was also purified on the same affinity matrix from both organs. All enzymatic forms are true AChEs and are poorly inhibited by CPE They show different increases in the maximum velocity (Vmax) and in the Michaelis constant (Km) values after CPF exposure. Consequently, catalytic efficiency of AChEs, as defined by the ratio Vmax:Km, rises in the gills and drops in the foot. This would produce an overexpression of AChE-specific mRNAs. The effect was longer lasting in the foot. The combined results indicate that overexpression of enzymes in the presence of organophosphate (OP) may be a consequence of OP resistance itself. Again, the resistance of the organism to CPF seem to depend mainly on the resulting increase in AChE content.
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PMID:Effects of chlorpyrifos on the catalytic efficiency and expression level of acetylcholinesterases in the bivalve mollusk Scapharca inaequivalvis. 1639 25

Relations between whole-body acetylcholinesterase (AChE) inhibition and changes in feeding and locomotor behaviours were investigated in adult male Gammarus fossarum during short-term exposure (96h) to the organophosphorous pesticide chlorpyrifos (CPE) and the carbamate pesticide methomyl (MT). AChE activity was measured after 24, 48 and 96h of exposure. The feeding rate was assessed after 48 and 96h of exposure and locomotor activity was measured at the end of the experiment. A concentration-dependent decrease of AChE activity and behavioural parameters was observed for both CPE and MT. However, these two compounds presented dissimilar modes of action since MT-induced effects appeared rapidly during the first 48h of the experiment and remained constant until the end of experiment, contrary to CPE-induced effects, which occurred gradually during the last 48h. For CPE, significant mortality was observed from 50% AChE inhibition, contrary to MT for which no mortality was observed despite 66% inhibition. These results suggest that, for CPE, the observed mortality was not directly related to AChE inhibition but that an additional toxic mode of action occurred. On the contrary, the feeding rate and locomotion impairment were directly correlated to levels of AChE inhibition for both chemicals, except for the lowest concentrations of MT for which an induction of the behavioural parameters was observed. Although CPE and MT have different modes of action (acting as indirect and direct inhibitors), the relations between AChE activity and inhibition of behavioural parameters were relatively close for these two compounds. This study provides a basis to interpret the biomarker AChE at the upper biological organisation level, on both the feeding rate and locomotor behaviour, which are known to be relevant ecological responses.
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PMID:Acetylcholinesterase activity in Gammarus fossarum (Crustacea Amphipoda): linking AChE inhibition and behavioural alteration. 1960 86